Climate Change: Day 22

November 18, 2014

Exam 3: Thursday, December 4th (final class period).
No class next Tuesday: Southeast Division of the Association of American Geographers, University of Georgia
Term project due date: Tuesday, December 9th. Email your HTML file to jelsner@fsu.edu.
Today: Are tornadoes becoming more frequent?
T or F: According to recent research by Professor Elsner and his students, the density of tornado reports today near cities is about the same as the density of reports in rural areas.

How to get weather station data

Weather Underground
Set Location: E.g., Portland Oregon, then Submit
Select Custom tab then Get History
Set the From/To dates Then Get History
Scroll to bottom and select Comma Delimited File
Copy the link

L = "http://www.wunderground.com/history/airport/KPDX/2014/11/1/CustomHistory.html?dayend=14&monthend=11&yearend=2014&req_city=NA&req_state=NA&req_statename=NA&format=1"
df = read.csv(L, stringsAsFactors = FALSE)
df$Date = as.Date(df$PST)
library(ggplot2)
ggplot(df, aes(x = Date, y = Min.Humidity)) + 
  geom_line()

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ggplot(df, aes(x = Max.TemperatureF, y = Min.VisibilityMiles)) +
  geom_point() + 
  geom_smooth(method = lm)

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Online R course

Last time: Are tornadoes getting stronger?

Tornado simulation

Problem

An estimate of how strong a tornado can get requires a continuous scale of intensity.
The EF damage scale is categorical.
A count of the number of tornadoes by EF category does not answer the question: Are tornadoes getting stronger?

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L = "http://myweb.fsu.edu/jelsner/TorBySTYR.txt"
df = read.table(L, header = TRUE)
head(df)

  Year ST nT   avgDoY medDoY
1 1954 AL  9 224.4444    339
2 1954 AR 26 115.2692    120
3 1954 CA  1 176.0000    176
4 1954 CO  8 136.7500    136
5 1954 CT  2 130.0000    130
6 1954 DE  1 182.0000    182

library(ggplot2)

ggplot(df, aes(x = Year, y = nT)) +
  geom_point() + geom_line() +
  facet_wrap(~ ST)

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Pilger NE Twin Tornadoes this June